Work-holding vise



Jam 6 1942 J. W. ROBERTSON 2,269,381

WORK-HOLDING VI SE WE/V702 JWKOBERTSON Jan. 6, 1942 l J. w. ROBERTSON2,269,381

WORK-HOLDING vIsE v Jan. 6, 1942 J. WROBERTSON WORK-HOLDING vIs'E 4sheets-sheet 5 Lik* Filed Dec. 30, 1940 vAftrap/viens Jan. 6; 1942 J. w.ROBERTSON 2,269,381

` WORK-HOLDING vIsE Filed Dec. so, 1940" 4 sheets-sheet 4 l .1w/@WwWaning,

Patented Jan. 6, 1942 AUNITED Isifn'lflsslearnNr OFFICE `Worm-HonnlncfvIsE John Watson Robertson. London, England ApplicationDecemhen 30,19.40. Serial No. 372,465 In Great Britain January 9, 1940 7 claims.del. 812-36) This invention relates'y to Workholding. visesY of the kindin which the screw co-operates witha half-nut capable of being movedinto and ont. of

engagement withvthe screw by means` of a.. cam v or other deviceoperating to displace the halfnut positively in both directions. Theinvention provides improved means wherebyk theA half-nut isy actuated asa consequence of the rotation of the screw.

According to this invention an additional screwthread is formedV on apartr of theI screw spindle which is normally unthreaded and thisadditional screwthread co-operates with a nut which is operativelyconnected to the half-nutso that rotation of the screw spindle causesthe nut to move lengthwise of the spindle tov engage or disengage thehalf-nut according to the direction of rotation of the spindle.

Preferably, the device whichactuates. the halfnut consists of a cammovable lengthwisey ofthe screw spindle and directly connected to thenut so that the cam is pushed by the nut. in one direction or the'otheraccording to the direction of rotation of the spindle.

Referring to they accompanying drawings, Figure 1 is a verticalsectional View of one'embodiment of the invention,

Figure 2 is a view similar to Figure l showing the parts in a differentposition.

Figure 3 is a horizontal sectional view on; line III-III in'Figure 1,

Figure 4 is a transverse sectional view on, the line IV-IV in Figure 3,and f Figure 5 is a view similar'to Figure 1 showing a modification.

Referring to Figures l to 4, the movable jawv II) ofthe vise has alongitudinal extension I 2 which slides within the body I4 of the visehaving the xed jaw I 6 cast integral with it. The screw .y

ends of which are bent as at 26, 2B to constitute t cams, the bentportions sliding in inclined holes the I 30, 32 respectively in the endwalls of the extenc sion I2. Figure 1 shows the half-nut 20 engaged withthe screw spindle I8, the cam bar 24, 26, 28 having been moved to theleft, and Figure 2 shows the halinut disengaged from the screw spindlein consequence of the cam bar having been moved to the right.

The normally unthreaded part of the screw spindle IS at the left-handend as viewed in Figures 1l to 3 isj formed with a multi-start screw-l.thread 34 of lquick pitch, flanked on both` sides by unthreaded portions36, 38, the diameter of which is not greater than the core rdiameter ofthe thread 34. Co-operating with the thread 34 is a nut 40 having adownward extension42engaging` ina slot 44 in the bar 24, the length vofthe slot being such as to provide lost motion between the nut 40, andthe bar 24. A light coil spring 46 is. interposed betweenthe nut 40 anda shoulder ,48. at' they left of the Unthreaded portion 36 and a similarspring 5.0 is vprovided which abuts against a collar 52'xed to thespindle I8 at the right of the. unthreaded portion 38.`

Assuming that the parts are in the position 'shown in` Figure l with thejaws gripping a workpiece 54, if the screw is turned counterclockwise asseen from the left to loosen the grip of the jaws, the screwthread 34will engage the ,screwthread within the nut 40, the nut being urged tothe right by the spring 46, and will drive the nutY to the, right, thenut of courser being held against rotation by the engagement of theextension 42 in the slot 44. This motion continues until the extension42` encounters the right-hand endof the slot 4,4. whereupon the bar willbe pushed to the right. and owing to the slopeof Athe cam, portions 26,28 the bar will move downwards as well as to the right, therebydisengaging the half-nul'l 20.4from the screw spindle I8 as-shown inFigure 2.

Normally the operator would cease turning the screw after thisv hashappened because he can then moye the movable jaw to any positionmere,-y ly by sliding itin or out. If, however,v he should continue toturn the screw the nut 40. will move still further to the right until itis clear of the screwthread 34. and rides freely upon the` unthreadedportion 38 of the spindle. Thus, it is impossible for the parts to bejammed or damaged by unnecessary turnlng of the screw spindle v in thecounterclockwise direction.

It will be appreciated 4that when the spindle is turned in the clockwisedirection the converse will take place; the nut, being urged to the leftby the spring 50, will at once engage the screwthread 34 and will bedriven to the left thereby pushing the bar 24 to the left andre-engaging the half-nut 20 with the screw spindle I8. Here again, owingto the fact that the nut 40 has moved clear of the screwthread 34 andrides freely upon the unthreaded portion 36, the screw spindle can beturned further to tighten the jaws upon the workpiece without having anyfurther effect upon the nut 4B or the bar 24, while at the ment with thescrew spindle I8, and to the left y to disengage it.

It may be desired to put the disengaging mechanism out of action so thatthe half-nut 20 is always in engagement with the screw spindle I8."

For this purpose a slide 56 is provided which ,is

guided in slots 58 in the sides of the extension I2`Y and is formed witha hook 60 which engages with the extension 42 of theI nut 4l) when theslide in moved to the right as seen in Figure 4. This hook thenmaintains the nut 40 out of engagement with the screwthread 34 and alsoprevents the bar 24 from moving to the right. Thus', the half-nut 20remains in engagement with the screw spindle I8.

I claim:

l. The combination with a work-holding vise having a half-nut mounted inguides to move into or out of engagement with the screw spindle, ofmeans for automatically engaging Vor disengaging the half-nut as aconsequence of the rotation of the screw spindle comprising anadditional screwthread formed on a part of the screw spindle which isnormally unthreaded, a nut cooperating with said additional screwthreadand an operative connection between the said nut and the said half-nut.

2. The combination with a work-holding vise having a half-nut mounted inguides to move into or out of engagement with the screw spindle, ofmeans for automatically engaging or disengaging the half-nut as aconsequence of the rotation of the screw spindle comprising anadditional screwthread formed on a part of the screw spindle which isnormally unthreaded, a nut co-operating with said additional screwthreadand an operative connection between the said nut and the said half-nut,a portion of the spindle adjacent said additional screwthread being leftunthreaded and of a diameter not greater than the core diameter of thethreaded portion, to receive the nut after the screw spindle has beenrotated by a certain amount in the tightening direction, whereby furtherrotation oi the spindle in that direction has no further action on thenut.

3. The combination with a work-holding vise having a half-nut mounted inguides to move into or out of engagement with the screw spindle, ofmeans for automatically engaging or disengaging the half-nut as aconsequence of rotation of the screw spindle comprising an additionalscrewthread formed on a part of the screw spindle which is normallyunthreaded, said spindle having an unthreaded portion adjacent the ed tobe slightly compressed by the nut after it has become disengaged fromthe additional screwthread. '4. The combination with a work-holding visel.having a half-nut mounted in guides to move vinto or .out oflengagement with the screw spindle, of means for automatically engagingor disengaging the half-nut as a consequence of the rotation of thescrew spindle comprising an additional screwthread formed on a part ofthe screw spindle which is normally unthreaded, a nut cooperating withsaid additional screwthread and an operative connection between the saidnut and the said half-nut, portions of the spindle adjacent saidadditional screwthread at either end thereof being left unthreaded andof a diameter not greater than the core diameter of the threadedportion, to receive the nut after the screw spindle has been rotated bya certain amount in either direction, whereby further rotation of thespindle has no further action on the nut.

5. A work-holding vise according to claim 4 wherein two coil springs,one on each of the unthreaded portions of the screw spindle, are adaptedto be slightly compressed by the nut after it has become disengaged fromthe additional screwthread at either end.

6. The combination with a work-holding vise having a half-nut mounted inguides to move into and out of engagement with the screw spindle, of acam device movable in a direction lengthwise of the screw and adapted todisplace the half-nut positively in both directions, and means forautomatically engaging or disengaging the half-nut asa consequence ofthe rotation of the screw spindle comprising an additional screwthreadformed on a part of the screw spindle which is normally unthreaded, anut (3o-operating with said additional screwthread and an operativeconnection between the said nut and the said cam device.

7. A work-holding vise according to claim 6, wherein the cam devicecomprises a bar having a straight middle portion parallel to the screwspindle and extending through a bore in the halfnut and having endportions bent to form cams sliding in inclined apertures in the movablepart of the vise.

JOHN WATSON ROBERTSON.

